Effective poroelastic behavior of a jointed rock

• Micromechanical formulation of poroelastic behavior of a jointed rock is presented.
• Poroelastic properties of parallel jointed rock are evaluated by Mori-Tanaka scheme.
• Micromechanical predictions are compared with cohesive model-based F.E solutions.
• Overall poroelastic properties for randomly jointed rock are derived analytically.

A main characteristic of rock masses is the presence of natural fractures (or joints) at different scales. The effective mechanical behavior of a rock medium is strongly affected by that of the joints, which can be viewed as cracks able to transfer stresses. The purpose of the present paper is to formulate the macroscopic poroelastic behavior for a rock with fluid-saturated joint network. The joints are modeled as interfaces whose behavior is described by means of generalized poroelastic state equations. Particular emphasis is given to the situation of small extension joints for which micromechanics-based expressions of the poroelastic properties are derived. Finally, the accuracy of the micromechanical predictions is assessed by comparison with 2D finite element solutions based on the cohesive model.